The activity of the group is focussed on diverse research lines whose common basis is the study of the structure-function relationship of proteins and bioactive peptides and the characterization of their properties and physiological role in particular systems of biotechnological and medical relevance.

The most traditional area of competence is the study and characterization of the pyridoxal-phosphate (PLP) dependent enzymes, particularly those of the fold type I, and the elucidation of their role in systems of potential biotechnological and biomedical impact. The dissection of the catalytic mechanism of several PLP enzymes and the analysis of their structure (e. g. serine hydroxymethyltransferase, GABA aminotransferase, glutamic decarboxylase, etc.) opens the possibility to engineer and modulate their activity and, therefore, to produce forms with novel functional and stability characteristics. Likewise, the knowledge of the detailed chemical properties can suggest how to design effective and specific inhibitors for specific PLP enzymes involved in metabolisms relevant for severe pathologies, like the serine hydroxymethyltrasferase for cancer and GABA aminotransferase for epilepsy. Expectedly, these inhibitors can reveal the way to the development of more effective drugs.

Fully integrated with the other research lines, is the in silico analysis of proteins to understand their chemical and conformational properties and their evolutionary and functional plasticity. Also to this respect, the PLP dependent enzymes form a very interesting family which is very ancient and, consequently, collects members which are very distantly related. We can therefore learn how the catalytic versatility of the PLP enzymes we know today could originate from an ancestral scaffold which underwent extensive remodelling during the divergent evolution without disruption of its basic architecture. The evolutionary story of the PLP enzymes can be archetypal of other protein families. Along the same lines, the wealth of structural information now available is exploited to understand the structural basis of the adaptation of several enzyme families (including the PLP enzymes) to extreme environmental conditions such as those experienced by the thermophilic or psychrophilic organisms. The group provides its expertise in bioinformatics also in the framework of collaborations with other groups of this and other universities.

Another research line involves the structural/functional characterization and mechanisms of action of antimicrobial peptides (AMPs) isolated from the skin of frogs as well as their role as effector molecules of innate immunity. AMPs are essential components of the innate immune system of all organisms and amphibian skin is one of the richest natural sources. The widespread and often empirical use of conventional antimicrobials has led to a drastic reduction in their therapeutic efficacy and to the emergence of resistance in a large number of microbes, which represent a serious life-threat. In addition, antibiotic therapy against Gram-negative bacteria is frequently associated with the release of their outer membrane components (endotoxin or lipopolysaccharide, LPS). LPS is a potent stimulator of immune cells and induces the secretion of several pro-inflammatory cytokines. Remarkably, when a prolonged activation of the immune system takes place, it leads to an unbalanced production of such cytokines, eventually resulting in the septic shock syndrome. Therefore, there is an urgent need to search for alternative anti-microbial agents to prevent resistance and with the potential to kill bacteria and to neutralize the toxic effects of LPS. Different from conventional antibiotics, which inhibit intracellular processes, cationic AMPs have the ability to select the target microorganism through electrostatic interactions with the anionic compounds of its cell surface (e.g. LPS) and to permeate the membrane, causing irreversible damage. Modes of action studies of AMPs in biological and artificial systems, such as those provided by model membranes, can open additional avenues for the discovery and development of new peptide-based anti-infective and anti-endotoxin drugs.

The research group spent during the past years many efforts to acquire expertise in the most recent and advanced techniques in the field of molecular biology, chemistry, analysis and purification of proteins. The availability of advanced equipment (protein sequencer, amino acid analyzers, mass spectrometers, etc.) supports the experimental research also in collaboration with many other research groups. Most recently, several research lines in the field of proteomics and genomics applied to biomedical research have been undertaken, such as the achievement of the inventory of the proteins expressed by Neisseria meningitidis, the structural characterization of peptides from Conus venom of potential pharmacological use, prion allotype profiling and set up of LC-MS methodologies for advanced clinical molecular diagnostics.

Substantial part of the research is represented by the attempt to engineer bacteria for the large-scale production of peptides or proteins of potential biotechnological use.

TECNOLOGIE IN POSSESSO DELL'U. O.

Enzyme kinetics analysis

Genetic engineering

Molecular graphics and in silico simulation of biological macromolecules